LYNCHBURG, Virginia - The CSX Corp train that derailed and erupted in flames in Lynchburg, Virginia, was carrying crude oil from the Bakken shale in North Dakota, the kind of oil involved in several other fiery derailments over the last few months, the railroad said on Thursday.

On Wednesday afternoon, some 15 cars derailed, several of which erupted in flames. Three tumbled down an embankment into the James River. No one was hurt in the accident.

State emergency managers estimated that a total of 30,000 gallons of crude oil had leaked into the river, creating a sheen up to 9 miles long, according to Bill Hayden, a public information officer with the Virginia Department of Environmental Quality.

Most of the slick has been contained by booms and some of the oil has burned off, he said. Drinking water has not been affected, Hayden said by phone from Richmond.

The U.S. Department of Transportation warned a few months ago that Bakken oil could be more flammable than other types of crude, and the incident is likely to add to calls for tougher regulations on the testing and transporting oil by rail, a booming business that has grown suddenly with the emergence of shale oil in placed like North Dakota.

Florida-based CSX said the train, which had two locomotives and 105 cars, was en route to Yorktown, Virginia.

A storage depot run by Plain All American in Yorktown can handle up to 140,000 barrels-per-day of such shipments. Plains did not reply to numerous calls for comment.

It was the sixth fiery derailment to occur in North America since a runaway train in Lac-Megantic, Quebec, derailed and exploded, killing 47 people last July. At least three of those involved oil from the Bakken, which is much lighter and therefore more flammable than most other varieties.

The accident occurred on the day U.S. regulators submitted a long-stalled proposal for tougher rail car design standards to the White House for review. The measure could raise costs for shippers and may require phasing out older cars.

CARS REMOVED

CSX said it has removed all cars that did not derail on Wednesday.

"Efforts continue to re-rail the remaining cars," the company said in a statement.

The National Transportation Safety Board is leading the investigation into the cause of the accident. No injuries were reported.

"It sounded like a wreck - a car wreck that went on for a long time," said Sarah Anderson, who was getting ready for work about four blocks from the scene when she heard the crashing noise. Anderson said she saw thick smoke climbing over downtown and flames that reached several stories high.

Nearly 640,000 barrels-per-day of the oil produced in North Dakota left the state aboard trains in February, according to latest data from state regulators.

Another CSX train carrying crude oil derailed in Philadelphia in January, nearly toppling over a bridge, but did not erupt. In an unrelated incident on Thursday morning, a CSX train carrying 8,000 tons of coal derailed about 200 miles northeast of Lynchburg, in Bowie, Maryland, according to a report from a local CBS affiliate.